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浏览/检索结果: 共6条，第1-6条 帮助 已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 Detection of two bright radio bursts from magnetar SGR 1935 + 2154 期刊论文 Nature Astronomy, 2021, 卷号: 5, 页码: 414 作者:  Kirsten, F.;  Snelders, M. P.;  Jenkins, M.;  Nimmo, K.;  van den Eijnden, J. 收藏  |  浏览/下载：45/0  |  提交时间：2021/11/18 Astrophysics - High Energy Astrophysical Phenomena  Abstract: Fast radio bursts are millisecond-duration, bright radio signals (fluence 0.1-100 Jy ms) emitted from extragalactic sources of unknown physical origin. The recent CHIME/FRB and STARE2 detection of an extremely bright (fluence ~MJy ms) radio burst from the Galactic magnetar SGR 1935+2154 supports the hypothesis that (at least some) fast radio bursts are emitted by magnetars at cosmological distances. In follow-up observations totalling 522.7 h on source, we detect two bright radio bursts with fluences of 112 ± 22 Jy ms and 24 ± 5 Jy ms, respectively. Both bursts appear to be affected by interstellar scattering and we measure significant linear and circular polarization for the fainter burst. The bursts are separated in time by ~1.4 s, suggesting a non-Poissonian, clustered emission processsimilar to those seen in some repeating fast radio bursts. Together with the burst reported by CHIME/FRB and STARE2, as well as a much fainter burst seen by FAST (fluence 60 mJy ms), our observations demonstrate that SGR 1935+2154 can produce bursts with apparent energies spanning roughly seven orders of magnitude, and that the burst rate is comparable across this range. This raises the question of whether these four bursts arise from similar physical processes, and whether the fast radio burst population distribution extends to very low energies (~1030 erg, isotropic equivalent).   Relationship between PD magnitude distribution and pulse burst for positive coronas 期刊论文 IET SCIENCE MEASUREMENT & TECHNOLOGY, 2018, 卷号: 12, 期号: 8 作者:  Tang, Ju;  Luo, Xinyu;  Pan, Cheng 收藏  |  浏览/下载：7/0  |  提交时间：2019/12/05 corona  partial discharges  Weibull distribution  SF6 insulation  pulse burst phenomenon  discharge magnitude distribution  two-parameter Weibull distribution  statistical characteristics  partial discharge  direct current voltage  UHF antenna  positive coronas  ultrahigh-frequency antenna  measurement impedance  insulation diagnosis  current pulse measuring circuit  pressure 0  3 MPa  time 24 h  SF6   Controllable preparation and photocatalytic activity of ZnO microstructures with different morphology 期刊论文 MICRO & NANO LETTERS, 2018, 卷号: Vol.13 No.4, 页码: 565-567 作者:  Xiaofang Qin;  Feng Wang;  Lixia Yang;  Yanbin Xu;  Zhenglong Yang 收藏  |  浏览/下载：53/0  |  提交时间：2019/12/26 catalysis  photochemistry  zinc  compounds  II-VI  semiconductors  wide  band  gap  semiconductors  crystal  growth  from  solution  semiconductor  growth  crystal  microstructure  crystal  morphology  X-ray  diffraction  scanning  electron  microscopy  photoluminescence  dyes  controllable  preparation  photocatalytic  activity  morphology  hydrothermal  synthesis  PEG4000  crystalline  phase  X-ray  diffraction  scanning  electron  microscopy  rod-like  ZnO  microstructures  flower-like  ZnO  microstructures  dumbbell-shaped  ZnO  microstructures  photoluminescence  spectra  emission  peaks  methylene  blue  degradation  ultraviolet  light  irradiation  temperature  120  degC  time  24  h  temperature  293  K  to  298  K  ZnO   Effect of anneal pre-treatment of polycrystalline aluminum sheets on synthesis of highly-ordered anodic aluminum oxide membranes 期刊论文 2010, 2010 Lu Zhang; Xiao Zhang; Cao Feng Pan; Jing Zhu 收藏  |  浏览/下载：5/0 A novel low-temperature method to grow single-crystal ZnO nanorods 期刊论文 2010, 2010 Dongliang Tao; Weizhong Qian; Yi Huang; Fei Wei 收藏  |  浏览/下载：2/0 Replacement of methane from quartz sand-bearing hydrate with carbon dioxide-in-water emulsion 期刊论文 energy & fuels, 2008, 卷号: 22, 期号: 3, 页码: 1759-1764 作者:  Zhou, Xitang;  Fan, Shuanshi;  Liang, Deqing;  Du, Jianwei 收藏  |  浏览/下载：69/10  |  提交时间：2010/09/23 The replacement of CH4 from its hydrate in quartz sand with 90:10, 70:30, and 50:50 (W-CO2:W-H2O) carbon dioxide-in-water (C/W) emulsions and liquid CO2 has been performed in a cell with size of empty set 36 x 200 mm. The above emulsions were formed in a new emulsifier, in which the temperature and pressure were 285.2 K and 30 MPa, respectively, and the emulsions were stable for 7-12 h. The results of replacing showed that 13.1-27.1%, 14.1-25.5%, and 14.6-24.3% of CH4 had been displaced from its hydrate with the above emulsions after 24-96 It of replacement, corresponding to about 1.5 times the CH4 replaced with high-pressure liquid CO2. The results also showed that the replacement rate of CH4 with the above emulsions and liquid CO2 decreased from 0.543, 0.587, 0.608, and 0.348 1/h to 0.083, 0.077, 0.069, and 0.063 1/h with the replacement time increased from 24 to 96 h. It has been indicated by this study that the use of CO2 emulsions is advantageous compared to the use of liquid CO2 in replacing CH4 from its hydrate.